A study of the acquistion of a group of English set-relational quantifiers in early childhood. Hypotheses about the order of mastery of these terms and the semantic knowledge associated with their understanding and appropriate use are made on the basis of the investigator's rational model for adult usage together with previous work on the child's developing understanding of set relations and predication. Predictions about comprehension are tested with a cross-sectional sample of 48 children aged 2 through 5 years. Parallel predictions about appropriate production are tested against longitudinal data for three children in the same age period. A preliminary study of the effects of selected stimulus variables on young children's verification of quantified sentences against pictures is also included.